Method of working ammonia-recovery producer-gas plants.



METHOD OF WORKING AMMO M QQQ T. RIGBY.

MA RECOVERY PRODUCER GAS PLANTS. APPUCATIVON' HLED MAY 13. 1911.

Patented June 1'; 191-3.

2 SHEETS-SHEET l.

62.4 fag 1 y 5330 7" i'ae na H T. RIG BY. METHOD OF WORKING AMMONIARECOVERY PRODUCER GAS PLANTS.

MLQ;

APPLICATION FILED MAY,13,19II.

I Patented June 1, 19153.

2 SHEETS-SHEET Z- Norking Ammonia-Recovery Producer-Gas THOMASE REGBY,O15 DUIEFRIE,

SCOTLAND, ASSIGNOR T0 NETCARZBONIZING LIHI, GE LONDON, ENGLAND.

METHOD OF WORKING AMMONIA"RECOVERY PRODUCER G-AS PLANTQ.

To'aZZ whom it may concern:

Be it known that I, THOMAS RIGBY, a sub- ;ect of the King of GreatBritain and Ireand, andresiding at Station Hotel, Dumfries, Scotland,have invented certain new and useful Improvements in Method of Plants,of which the following is a specification. I

The invention has for its object to greatly reduce the cost ofproduction of briquet fuel made from brown coal peat lignite or thelike.

In ammonia recovery producer gas plants large quantities of water-vaporor steam are required. for the purpose of keeping down the temperatureof combustion in the gas producers with the object of making largequantities of ammonia from the original nitrogen in the fuel andconserving it after it is made and passes away in the producer gas untilit is finally recovered in the later stages of the process. As a rule, alarge portion of this vapor has to be raised from auxiliary sources,with a consequent expense in fuel, but, if the gas is to be used for thepur poses of a briquetin plant, considerable economies may be e acted inthe manner hereinafter described. in briqueting plants for treatingbrown coal or peat, whether air dried or wet carbonized, provision isusually made for evaporating the moisture from the fuel. For instancewhen using brown coal in such a plant the fuel often contains fifty tosixty per cent. of moisture by weight in its. composition and. the sameconditions usually prevail when using peat in a similar plant. In thisinvention I propose to utilize all or a portion of this vapor in anammonia recovery gas plant worked in conjunction with a fuel briquetingplant'by mixing the vapor with air compressing the mixture, and passingit under pressure into the air supply ofthe gas producers to replacewholly or partially the auxiliary steam usually employed for thispurpose.

In the accompanying drawings are illustrated three arrangements of anammonia recovery producer gas plant combined with a peat or the likeiuelbriqueting plant for carrying my present invention into effect.

Figures 1 and 2 are diagrammatic, partly sectional, elevations ofcombined ammonia recovery gas producing and fuel briqueting pts. Fig. 3is also a diagrammatic elevapeclllcation of Letters Patent.

Patented June 1., 19115.

application filed Key is, 1911. Serial in. 626,955.

tion partly sectional, having in the connections between the combinedplants a dust. ,7

extractor after the and independently and a peat superheater in advanceof the gas producer.

peat drier, a compressor,

fired steam superheater,

In the arrangement illustrated by Fig. l,

the other end where it is removed by a screw conveyer (Z or othersuitable appliance-and delivered Where required.

The vapor, generated from the peat or the 1 like by the process ofdrying in thecylinder 0, passes upward through the chimney 6. At the topof the chimney shaft e.-I mount a pair of flap valves f, which aregeared together at f and operated by a chain f from a hand wheel f inorder to control the amount of vapor, if any, allowed. to escape intothe atmosphere.

In the arrangement illustrated by Fig. 1 I make a direct connectionbetween the chimney shaft e and the air supply to the producer, andarrange the regulation in such a manner that only the quantity of vaporactually required is taken from the chimney shaft, the remainder beingallowed to escape designed in such a manner that any dust present in theair or vapor is thrown out by centrifugal action; The type of pressureraising apparatus I propose'to use with this method is a blower or fanw, driven by a belt o from a pulley v or in other eonvenient manner, andwhich forces the air and vapor mixture from the drier c of the fuelbriqueting plantthrough the pipe 71 into the air supply pipe 2' of thegas producer h.

The fan w by centrifugal action throws out the dust present in the airand vapor l'IllK- ture and discharges it through a pipe w" into a lutew, from which it can be recovered and returned to the system for thepurpose of briquet making.

In the form last described, only a single pressure raising device hasbeen shown as employed to raise the pressure of the air and required forthe gas producers.

vapor mixture from the fuel briqueting plant to the degree requiredbefore it is passed into the gas producer system and it will beunderstood that these arrangements are shown as examples only.

There is in most cases a surplus of vapor produced and in some cases Iallow the surplus to escape through the valves 7 and only pass through,the pressure raising device and centrifugal dust extractor w the actualvapor I prefer however usually to pass the WllOlGOf the vapor producedfrom the driers through the combined pressure raising device andcentrifugal dust extractor w as by this means the whole of the dust isrecovered in the process, and if there is an excess of vapor I provide arelief valve or outlet valve i and discharge pipe i on the delivery sideof the allowing the excess vapor to escape into the atmosphere freedfrom objectionable dust.

- trated, I show the blower v forcing air through the pipe 2' into thedrier a, whence the vapor is discharged into the chamber 6 correspondingto. the chimney shaft 6 in the previous arrangement, and conducted by.the pipe j through the dust extracting de- .Vice in and through the pipe2" to the a r supply pipe 11 of the gas producer h. It is vital that inan arrangement of this kind the .dust extracting device, which may be ofany suitable kind, be placed between the outlet of the drier and theinlet of the gas producer system, as a larger quantity of dust is carried over with the vapor under a pressure than'when working the drier ator about atmospheric pressure.

When the briquetmg plant is constructed to treat wet carbonized peat inthe manner "to the extent required, and I super-heat the air and vapormixture, and preferably comress it either before or after superheatingefore passing it to the peat heating or supressure raising device forthe purpose of I illustrate such an arand then subjecting it at atemperature of: one hundred and twentydegrees Centigrade: or higher topressure in an open die briquet-- ing press.

As will be seen in Fig. 3 the air and vapor mixture after leaving thedust separator it passes through the air compressor g and I then throughan independently fired superheater 2 whence the superheated vapormixture passes to the peat superheater of the briquetingplant in whichthe peat is fed into a hopper 1 and passes to the peat super:

heater 2 whence it is delivered in a highly heated state through thepipe 3 direct to the briqueting press 4, the end of which only is shown.

From the drawings it will be seen that the air and vapor mixture afterhaving been superheated in the superheater 2 passes through the pipe 5into the peat superheater 2, the temperature of which it assists infpatented operamaintaining, and passes thence through the.

pipe 6 to the air inlet pipe 2' of the gas pro ducer system as beforedescribed.

I find it desirable in practice in most cases that the quantity of airpassing through the tubes in contact with the peat in' the driers,

shall be such that the vapor leaving the chimney is at a temperature inthe neighborhood of eighty five degrees centigrade. lPhe air is thussaturated with vapor at the same temperature and a proportion of air tovapor is obtained which is advantageous to the working of ammoniarecovery gas producers= I may however any desirable proportion of airthrough the driers to obtain any suitable temperature of saturation.

When the material to be gasified or to be dried in Schultz drierscontains 55% of water is very common when working with peat or lignite)there is evaporated when ma ingd tons of briquets perhour approximately4.7 tons of u "ater-vapor per hour,

If this is passed mixed with air saturated say at 85 C. there issufficient vapor to supply the'ammonia producer plantw i-th all itrequires without adding steam in the best .case, in others it isnecessary to supply additional steam if the same degree of saturation isused as more fuelhas to be gasified for the purpose of maximum ammoniarecovery;

I may in such cases pass all the air required for the gas producersthrough the driers with the result that it would leave saturated at alower degree than that above indicated I the auxiliary steam beingadded; prior to its entrance to the gas producers. The satura: tion maynot however in any case be less than corresponding to "75 C,an'din-sucha for this purpose. In such cases I with fuel containingmsrsee oase auxiliary steam has to he added hefore entering the. gasroducers,- when working of water. Ohviously a lower or higher saturationof the air supplied to the gas producers may he used when Workingwithfuels containing higher/hr lower percentages of water in theircomposition, the being varied with the object of obtaining at all timesmaximum yield of ammonia.

If I wishto raise some aumiiary steam producers as is weiibrown with theammonium recovery type of; giant it is desirfor asification cause thesaturation of the mixture leaving the driers to be higher even so highas 98 or 99 C. the mixture of air. and Water vapor (princiahle to usethe air ntends pally water vapor) thus passed being preferably'delivered under pressure into the air main between the regeneratingapparatus and the gas producers;

' The result of mixing the highly saturated mixture from the'driers withsaturated air from-the regenerative apparatus at a temperature ofapproximately C. is, that the al mixture of air and steam enterin thegas producers is in the neighborhood 0 859 C. or whatever saturation isconsidered desirable for obtaining maximum yields of ammonia.

Having now described my invention what I claim as new and desire tosecure by Letters Patent is v The method of'utilizing the vapors neretedin the driers of a briquetmg p ant consisting in mixing them with air insuit able proportion, compressing the mixture, extracting suspendedmatters and passing the mixture at the desired pressure to a gasproducer system; substantially as and the purposes described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS RIGBY.

Witnesses:

E. C. WALKER, a P. A. Ou'rnwam.

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